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Biomedical subjects

H J Neijens

Publications and source records attributed to H J Neijens.

At least 91 records · Page 5Linked to original sources
PubMed1989

Prenatal diagnosis and genetic counseling of cystic fibrosis.

The number of DNA markers at the chromosome 7-locus of the putative CF gene has markedly increased in recent years, also as a result of intensive research into the possible "candidate" gene. In studies of families with one or more affected children, 97.5% of families are now fully informative, allowing a prenatal diagnosis by chorionic villus sampling in the 10th week and DNA-analysis, which will usually give now a diagnosis with a remaining risk of less than 1%. The microvillar enzyme test in amniotic fluid after amniocentesis in the 18th week will remain an alternative for couples who have a high prior risk, but are either not informative at DNA analysis, or where no information on a (deceased) index case (previous affected child) is available. The risk for a wrong classification is in the order of a few percent (in a 1:4 prior risk case) and careful discussion of the limitations are needed when this test is applied to cases with a lower prior risk. The linkage disequilibrium established for a number of RFLP's (Restriction Fragment Length Polymorphisms), as detected by various probes and various restriction enzymes around the CF locus has opened the possibility to refine the risk estimation of heterozygosity for individuals outside families with CF-affected children. The presence of certain haplotypes may change the risk for being CF heterozygote from +/- 1:7 to 1:250, as compared to a population risk of +/- 1:25.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosomes, Human, Pair 7↗
PubMed1989

Strategies and perspectives in treatment of respiratory infections.

Bronchopulmonary infections in CF have a number of special features. The pathophysiology is determined by consequences of the basic CF defect and interactions with host defence systems, leading to chronic inflammation induced by Staphylococci and subsequently Pseudomonas. This results in lung tissue damage, various complications and eventually respiratory insufficiency. Policy of treatment is to combat infectious exacerbations and lung tissue destruction as much as possible. Factors in optimal treatment such as strategies, indications for therapy and selection of antibiotics are discussed.

Anti-Bacterial Agents↗
PubMed1989

Respiratory syncytial virus infections in children admitted to the intensive care unit.

During the winter of 1986-1987, 64 children with respiratory syncytial virus (RSV) infection were admitted to our hospital. The diagnosis was made by direct immunofluorescent antibody technique. Twenty-three children (36%) needed intensive care treatment. Nearly 11 (52%) had a preexisting disease state, identified as a risk factor i.e., prematurity (n = 8), bronchopulmonary dysplasia (n = 2), congenital heart disease (n = 1). Twelve patients (50%) were intubated and ventilated. Conditions for intubation and ventilation were repetitive apnea with or without bradycardia (n = 4), clinical deterioration (n = 3) or hypercarbia (n = 5). Seventy-five percent of the patients who needed intensive care management were under three months of age compared to 34% of the children who were admitted to the clinical ward. The mean age for ventilated patients was 7.9 weeks. The mean duration of ventilation was 5.5 days. Volume controlled ventilation was initially applied to all patients. Pulmonary complications (atelectasis, pneumonia, pneumothorax or adult respiratory distress syndrome) were present in 15 (65%) IC patients. Nine (39%) of them also had symptoms of inappropriate antidiuretic hormone secretion (IADHS). Only two patients had symptoms of IADHS and two others had convulsions. Three children (5%) died as a result of respiratory insufficiency. Two of these infants belonged to the risk group.

Bronchiolitis↗
PubMed1988

Properties of human basophils isolated by fluorescence-activated cell sorting.

The aim of the current study was twofold: (1) to consider the applicability of fluorescence-activated cell sorting (FACS) to basophil isolation from small blood volumes and (2) to compare basophils obtained from children with asthma to basophils from healthy children. With FACS, basophil suspensions were prepared with a purity of 84% (range, 75% to 95%) and a recovery of 20% (range, 15% to 30%). The purified basophils had a total histamine content of 1.6 +/- 0.12 pg per cell, not differing significantly from total histamine content observed in "total" leukocyte suspensions (1.4 +/- 0.07 pg per basophil). The same was true for IgE receptor-mediated histamine release (29 +/- 4% versus 27 +/- 4%) and for ionophore A23187-induced histamine release (41 +/- 6% versus 51 +/- 9%). Sorted basophils from subjects with asthma released more histamine after IgE receptor activation (0.67 +/- 0.09 pg per cell) than basophils from healthy children (0.40 +/- 0.04 pg per cell; p less than 0.02). Expressed as percent release, no significant difference was observed (37 +/- 3.2% versus 30 +/- 2.7%). Ionophore A23187-induced histamine release did not differ significantly between subjects with asthma and control subjects, neither expressed as picograms per cell (1.21 +/- 0.17 pg per cell versus 1.02 +/- 0.11 pg per cell) nor expressed as percent release (66 +/- 4.4% versus 74 +/- 3.2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Differentiation, B-Lymphocyte↗
PubMed1988

Malabsorption in cystic fibrosis: mechanisms and treatment.

Malabsorption of nutrients in cystic fibrosis (CF) has a multifactorial origin. The factors involved in malabsorption include malfunction of the exocrine pancreas and liver, bile acid metabolism, and disordered intestinal resorptive processes. Therapeutic measures presently employed are only partially effective. Improvement of fat malabsorption is attained by using a pancreatic enzyme supplement consisting of pH-sensitive, enteric-coated microspheres (microsphere preparations) that prevent enzyme degradation in the stomach and travel with the chyme to the small intestine. Microsphere preparations, however, do not improve bile salt deficiency. The detergent Tween-80, given orally to simulate bile salt activity, does not improve fat absorption. The mucus viscosity is probably enhanced in the intestinal epithelium of CF patients and can be decreased by N-acetylcysteine, which breaks down sulfide bonds. However, the addition of a high oral dose of this mucus solvent to pancreatin preparations does not improve fat absorption. Further studies on the disturbed intestinal resorptive mechanism seem warranted since recent investigations point to an abnormal chloride secretion as the primary defect in the intestinal epithelia of CF patients.

Acetylcysteine↗
PubMed1988

Oligoclonal T cell proliferative disorder in combined immunodeficiency.

Oligoclonal lymphoid proliferations may occur in immunocompromised patients and in the elderly. So far these proliferations have been shown to be of B cell origin. We describe a patient with a combined immunodeficiency, characterized by profound hypogammaglobulinemia and the initial absence of T lymphocytes in the peripheral blood (PB). From the age of 4 yr CD3+ T cells appeared in PB in rising numbers. These cells mainly expressed the CD4-/CD8+ phenotype (CD4/CD8 ratio: 0.1). Despite the emergence of T lymphocytes no proliferation of PB mononuclear cells could be induced with phytohemagglutinin, concanavalin A, or pokeweed mitogen. Between the ages of 4 and 6 yr the patient gradually developed hepatosplenomegaly and an interstitial pulmonary infiltrate of unknown origin, necessitating biopsies of both liver and lung. Infiltrates consisting of CD8+ T lymphocytes were found in the liver as well as the lung. CD8+ T cells were also abundant in the bronchoalveolar lavage fluid. Southern blot analysis of mononuclear cells from PB and of a lung biopsy specimen was performed to investigate if a clonal T cell population was involved. Analysis of the T cell receptor beta genes revealed that at least three expanded T cell clones were present in PB, one of which had invaded the lung. Thus far, i.e. 2 yr after the initial detection of clonal T cell receptor beta gene rearrangements, there have been no clinical or histologic signs of malignant behavior. We conclude that this combined immunodeficiency patient has a benign oligoclonal T cell lymphoproliferative disorder. Similar proliferations might well occur in other immunodeficiency states, whether primary or acquired.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Effect of long-term treatment with inhaled corticosteroids and beta-agonists on the bronchial responsiveness in children with asthma.

Airway inflammation is assumed to be an important determinant in increased bronchial responsiveness (BR). We tested the hypothesis that treatment with an inhaled anti-inflammatory drug (i.e., budesonide) but not with an inhaled beta-agonist (i.e., terbutaline) would reduce BR in children with asthma and with minimal or no bronchoconstriction. Twelve patients were treated with budesonide and seven with terbutaline for 6 months. BR decreased in 11 patients receiving budesonide and was significant in seven patients. BR decreased in none of the patients receiving terbutaline. FEV1 demonstrated a small increase with budesonide but remained unchanged with terbutaline. Except in one patient who received terbutaline, the clinical effect was good. We conclude that inhaled corticosteroids but not inhaled beta-agonists will decrease persistent BR in most children with asthma.

Administration, Inhalation↗
PubMed1987

Deficiency of immunity to Mycobacterium avium that can be restored by allogeneic lymphocytes.

A 3-year-old girl developed a disseminated Mycobacterium avium infection despite treatment with eight antimycobacterial drugs. She had no pre-existent general humoral or cellular immunodeficiency. In the course of the disease B lymphocyte areas in the lymphoid tissues were replaced by histiocytes and an IgM and IgA deficiency evolved. The patient still made antibodies to concomitant micro-organisms and to transfused blood cells. Peripheral blood mononuclear cells (PBMC) had normal responses to mitogens and various antigens in vitro. However, she lacked any response to mycobacterial antigens, in vivo and in vitro. The defect appeared not to be dependent on immunosuppression by lymphocytes or monocytes or on deficient antigen presentation by monocytes. because a genetic origin could not be substantiated, acquired immunological paralysis for mycobacterial antigens was the most likely explanation. Addition of irradiated PBMC from her HLA-A, -B, -C and -DR phenotypically identical father, transferred a response to mycobacterial antigens of the patient's PBMC in vitro. We concluded that the disseminated M. avium infection was accompanied by a selective deficiency of the lymphocyte response to mycobacterial antigens which could be restored by allogeneic antigen responsive lymphocytes.

Antigens, Bacterial↗
PubMed1986

Respiratory tract disease in systemic lupus erythematosus.

Respiratory tract involvement is common in adults with systemic lupus erythematosus (SLE). Although SLE in children usually follows a more severe course than in adults, there are few reports on pulmonary disease and lung function in children with SLE. We performed lung function tests and chest x ray examinations in eight children with SLE (mean age 11.1 years), three of whom presented with pulmonary symptoms. A high prevalence of lung involvement was found, including interstitial or localised infiltrations, pleural effusion, a restrictive impairment of lung function, and dysfunction of the diaphragm. Three patients required artificial ventilation. Two main mechanisms of ventilatory impairment seem to occur in children with SLE: firstly, acute interstitial pneumonia, which rapidly improves on treatment with steroids, and, secondly, restriction of lung volume, mainly due to respiratory muscle weakness.

Acute Disease↗